Spherical grinding apparatus



July 3, 1951 D. A. MIDDAUGH ET AL 2,558,771

SPHERICAL GRINDING APPARATUS 2 Sheets-Sheet 1 Filed July 23, 1947 INVENTOR. DENNIS A. MIDDAUGH y WALTER MS CHICHTELL y ,1951 D, A. MIDDAUGH ETAL 2,558,771

SPHERICAL GRINDING APPARATUS Filed July 25, 1947 2 Sheets-Sheet 2 INVENTOR. NM 3 A. MIDDAUGH LTER M. SCH ICHTELL ATTOR EY Patented July 3, 1951 EFlCE SPHERICAL GRINDING APPARATUS Dennis A. Middaugh, Jersey City, N. J., and Walter M. Schichtell, Putnam Lake, N. Y.

Application July 23, 1947, Serial No. 763,124

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 3 Claims.

This invention relates to improvements in tools, and more particularly pertains to improvements in universal grinding attachments for lathes.

In machining a connecting rod having a hardened ball portion integral one end of said rod, it has been conventional practice to rough the connecting rod ball to within .003" of finished size with a radius tool, harden the ball, and then employ a cast-iron lapping-plate to lap the ball to finished size and attain a high finish thereon. However, the lapping process is so slow that no more than .003" can be allowed for the finishing operation, even though .003 is not always sufilcient to clear the surface of the ball, due to warping and pitting of the metal that occurs during hardening. As a result, the requirements of a high and uniform finish for the ball of the connecting rod is, frequently, not met, and time, labor and material expended fruitlessly. In addition, lapping is a manual process, dependent in .large measure on the skill of the operator and at best excessively slow and productive of non-uniform results.

The primary object of the invention is to provide a universal grinding attachment for a lathe and a method of grinding an object such as the ball of a connecting rod.

Another object is to provide a universal grinding attachment of simple and durable construction adapted to grind an object such as the ball end of a connecting rod.

Still another object is to provide a universal grinding attachment adapted to machine a ball accurately, speedily and automatically.

A further object is to provide a universal grind- I.

ing attachment adapted to machine a ball uniformly and symmetrically through a depth of cut heretofore deemed inordinate.

Another object is to provide a novel method of machining a ball to a high finish.

Fig. 3 is a section taken on the line 3-3 of Fig. 2;

Fig. 4 is an elevation, partly broken away, taken in the direction of the line 4-4 of Fig. 2; and

Fig. 5 is an isometric view of an associated holder for a grinding-wheel cutter.

Similar numerals refer to similar throughout the several views.

The grinding attachment, generally, includes means for positioning a grinding-tool assembly upon the carriage of a lathe and relative a workpiece, 'and for securing said grinding-tool assembly in selected position, a grinding-tool assembly adapted to position a grinding-tool relative a workpiece, to secure said grinding-tool in selected position and to rotate said grinding-tool, and means to oscillate said grinding-tool assembly in an arcuate path.

The means for positioning and securing the grinding-tool assembly includes a yoke l I carried on an arm I3, the mounting of said arm [3 being receivable by a conventional compound rest. Such rest includes tool-feed carriage 15, which carries block ll slidably in T-slot H?) of said toolparts feed carriage. Block ll mounts threaded bolt .23

having a tightening-nut 25, a tubular spacer 21 that is larger in diameter than the bore in arm [3 acting as a bearing or clamping washer which nut 25 acts against to clamp arm l3 in place. Block H is prevented from sliding relative to carriage [5 by rotation of tightening-nut 25, and thus secures yoke ll against movement relative to carriage l5. Said carriage I5 is slidable rectilinearly upon carriage-plate 21 by means of crank 29. Carriage-plate 21 is rotatable relative to lathe-carriage 3! by means of crank 33, while nuts 35 are provided to secure carriageplate 2? against such rotation.

Yoke l I, in secured position, is disposed normal to the surface of lathe-carriage 3!, with legs 31 and 39 of said yoke in a common vertical plane, and with bore 4! in leg 3! and bore 43 in leg 39 (see Fig. 3) having a common vertical axis.

The grinding-tool assembly includes a yoke 65 having legs M and 49, and an arm 5| forming a base for the motor table hereinafter described. The facing ends of studs 53 and 55 are pointed to fit conical bores or recesses in the confronting faces of the legs 41 and 49. Said studs 53 and 55 threadedly fit the bores 4! and 43 in legs 3'! and 39 respectively, and are provided with bolt heads 5! by means of which said studs are rotated to obtain their desired position and desired tightness of fit of the ends in the bores or sockets in arms 4! and 49. Lock nuts 58 are also provided on said studs 53 and 55 for retaining said studs in adjusted position. The longitudinal axes of studs 53 and 55 are parallel or common to facilitate rotation of yoke 45 with said studs as pivot points.

Table 59 is mounted slidably upon arm 5i, keyway 6! of said table riding on key 63 of arm 5 5. Fine adjustment of the position of table 59 relative arm 5i is obtained through suitable feeding means (not shown) actuated by wheel 54, which carries graduated disc 95. Preferably, the graduations of disc 65 indicate rectilinear feed of the order of .0005 or less.

Motor 91 is mounted on table 59, and drives shaft 69 through belt linkage H. Said shaft 59 extends through yoke 45 and carries grinding wheel I3 between legs 41 and 49 of yoke 45, the axis of said shaft being disposed in the plane of said legs and parallel the surface of lathe-carriage 3|.

Leg 49 of yoke 45 carries a pan I5, said pan being so positioned and proportioned as to carry a coolant and dust-absorbent solution in which the ball of the connecting rod being ground is partially immersed during the performance of the grinding operation.

The means to oscillate the grinding-tool assembly in an arcuate path includes the following structure: A disc or turntable I! is mounted on a support 79 (see Fig. 4) by bolts BI, and said support is mounted on the end of a shaft 83, so that said turntable is carried normal to said shaft. The shaft 89 is secured rotatably in the bearing 85 of an arm 9? extending from lathe carriage 3!, whereby the face of said turntable is secured parallel to the face of said lathe carriage. Gear 89 is mounted on shaft 83, in mesh with the conventional worm or lead-screw 9! of the lathe and rotated thereby.

Plate 93 is mounted slidably in the radial slot 95 of turntable I1 and is provided with a plurality of setscrews 9'? adapted to secure said plate against movement relative said slot. Connecting rod 99 is threaded into sleeve I91, which carries ball I93 at the end of said sleeve distal rod 99, said ball I93 being mounted rotatably in knuckle I95, which in turn is mounted on plate 93, normal thereto. Thus, connecting rod 99 is adapted to rotate universally in knuckle I95. The

opposite end of connecting rod 99 is threaded into sleeve I91, which carries ball I99 at the end of said sleeve distal rod 99, said ball I99 being mounted rotatably in knuckle HI (see Fig. 3), which in is mounted on the nether face of base 5I, normal thereto. Thus, connecting rod 99 is adapted to rotate universally in knuckle HI.

In aligning the grinding-tool assembly, a holder for a diamond cutter, shown in Fig. 5, is employed. Said holder comprises a C-clamp II3 mounting an arm H5 and having a plurality of thumb-screws ill adapted to secure said clamp upon yoke II, a diamond cutter IE9 secured in the end of said arm distal said clamp by a setscrew IZI, and a score or mark I23, which can be aligned with a score or mark I25 on yoke II to facilitate accurate positioning of said holder on said yoke. With the grinding-wheel I3 (preferably a hollow mill grinding-wheel) mounted on shaft 99, the holder mounted on yoke i I, and said yoke II so positioned that yoke 15 rotates on an axis that passes through the longitudinal axis of the lathe chuck, said diamond cutter is employed to cut the face of grinding-wheel to the radius to be ground. Such cutting is effected by rotating grinding-wheel F3 on shaft 59 by means of motor 61 and oscillating yoke by means of connecting rod 99, turntable 'I'I, gear 89 and feed screw 9|.

When the grinding-Wheel I3 has been cut to desired shape, the holder is removed from the yoke and the workpiece I2? mounted in the chuck I29 of the lathe. A suitable coolant, such as a solution of sodium carbonate and water, is poured into pan I5, said solution serving to cool the workpiece, which is partly immersed in it, and to suppress dispersion of material abraded from the workpiece and from the grinding-wheel.

With the compound rest of the lathe so adjusted and secured that the common axis of bearings 53 and passes vertically through the center of the connecting-rod ball to be ground, operation of the device is apparent. The lathe chuck I29 rotates the workpiece, motor 61 rotates hollow mill grinding-wheel I3, and the grindingwheel assembly is oscillated through an arcuate path (of desired radius, by virtue of the adjustment of wheel 54, which feeds table 59), said path being of an extent determined by the positioning of plate 53 relative radial slot 95, since such positioning determines the throw of connecting rod 99 as it is moved by turntable IT, which in turn is driven by lathe lead screw 9I through gear 89 and shaft 83. It is to be noted that further adjustment of the throw of connecting rod 99 can be effected by adjustment of the position of said rod relative sleeve IIlI or sleeve I93, or both.

Various modifications and changes can be made in the subject device without departing from the scope of the invention. I

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

We claim:

1. In a lathe having a driving means, a chuck carried in the headstock thereof and adapted to secure a workpiece on said lathe, a compound rest carrying a tool-feed carriage adapted to pre-- sent a tool against such workpiece and a longitudinal-feed lead screw carried by said lathe and disposed parallel to the axis of rotation of said chuck, said chuck and lead screw being rotated by said drivingmeans, a universal grinding attachment comprising a first yoke mounted on said carriage, a second yoke having legs pivoted on threaded studs mounted in the legs of said first yoke, said studs being adapted to elevate and depress said second yoke relative said first yoke, a grinding tool carried by said second yoke,

* means to rotate said grinding tool mounted on said second yoke, a disc having a radial slot mounted rotatably on said lathe, said disc being rotated by said lead screw, and a connecting rod secured in said slot and to said second yoke whereby said second yoke is oscillated on the axis of said studs.

2. In a lathe having a driving means, a chuck carried in the headstock thereof and adapted to secure a workpiece on said lat-he, a compound rest carrying a tool-feed carriage adapted to present a tool against such workpiece and a longitudinal-feed lead screw carried by said lathe and disposed parallel to the axis of rotation of said chuck, said chuck and'lead screw being rotated by said driving means, a universal grinding attachment comprising a first yoke mounted on said carriage, a second yoke having legs pivoted on studs mounted in the legs of said first yoke, said second yoke being rotatable on an axis intersecting the axis of rotation of said chuck, a grinding tool carried by said second yoke, said studs being threaded in bores in the legs of said first yoke to provide means to elevate and depress said second yoke relative said first yoke, means to rotate said grinding tool mounted on said second yoke, a disc having a radial slot mounted rotatably on said lathe, a gear carried by said disc, said gear being rotated by said lead screw, a plate mounted slidably in said slot,

means to secure said plate against movement relative said slot carried by said plate and engaging said disc, and a connecting rod secured to said plate and to said second yoke whereby said second yoke is oscillated on the axis of said studs.

3. In a lathe having a driving means, a chuck carried in the headstock thereof and adapted to secure a workpiece on said lathe, a compound rest carrying a tool-feed carriage adapted to present a tool against such workpiece and a longitudinal-feed lead screw carried by said lathe and disposed parallel to the axis of rotation of said chuck, said chuck and lead screw being rotated by said driving means, a universal grinding attachment comprising a first yoke mounted on said carriage, a second yoke having legs pivoted on studs mounted in the legs of said first yoke, said second yoke being rotatable on an axis intersecting the axis of rotation of said chuck, a grinding tool carried by said second yoke, said studs being threaded in bores in the legs of said first yoke to provide means to elevate and depress said second yoke relative said first yoke, means to rotate said grinding tool mounted on said second yoke, a disc having a radial slot mounted rotatably on said lathe, a gear carried by said disc, said gear being rotated by said lead screw, a plate mounted slidably in said slot, a knuckle secured on said plate, means to secure said plate against movement relative said slot carried by said plate and engaging said disc, and a con- 6 necting rod having a ball in one end carried universally in said knuckle, the other end of said rod being secured rotatably to said second yoke.

DENNIS A. MIDDAUGH. WALTER M. SCHICHIELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 215,267 'Covel May 13, 1879 513,631 'Conrader Jan. 30, 1894 513,632 Conrader Jan. 30,1894 523,883 Covel July 31, 1894 574,855 Schofield Jan. 5, 1897 657,905 Lea septall, 1900 819,628 Alton May 1, 1906 1,010,565 Ahlberg Dec. 5, 1911 1,261,765 Challet Apr. 9, 1918 1,274,591 Quimby Aug. 6, 1918 1,325,789 Johnsson Dec. 23, 1919 1,698,909 Currier Jan. 15, 1929 1,756,908 Baumberger Aug. 29, 1930 1,941,598 Cleveland Jan. 2, 1934 1,969,238 Robinson Aug. 7, 1934 2,174,213 Postma Sept. 26, 1939 2,271,743 Nagy Feb. 3, 1942 2,295,014 Schmuldt Sept. 8, 1942 2,381,449 Holman Aug. 7, 1945 FOREIGN PATENTS Number Country Date 26,297 Switzerland Mar. 22, 1902 112,349 Great Britain Jan. 10, 1918 OTHER REFERENCES Grinding Wheels and Their Uses, by Johnson Heywood, published by the Penton Publishing 00., Cleveland, Ohio, in 1938. 

